New Library UI - non-required "Required" metadata

I have an issue with the way the metadata works in Sharepoint when document check-in/check-out is being used to manage document versions.

Generally, the purpose of using check-in/check-out is to manage the version of a document for traceability and other reasons. The only time the version of the document should change is when the content of the document changes and this include changes to some types of metadata.

However, there is 2 types of metadata associated with a document:

1. The metadata that is part of the document content. If this changes so does the version of the document. For example: Title, Author, Publish date.
2. Metadata that is used for classification (taxonomy) of the document for storage or searching purposes. In this case the metadata can be changed without changing the content or version of the document. For example: If a (physical) book is out in a (physical) library it might be listed under several subjects.

The problem in Sharepoint is that if check-in/check-out is required there is no way (as far as I know) to change metadata associated with the document without raising the version number.

Sharepoint needs some mechanism that allows classification (taxonomy) metadata to be updated without changing the version number.

If this could be done, then the taxonomy provided by the term store would become a very powerful feature.